Compressor for fluid pressure systems



Sept. 22, 1936. w OLIVER 2,054,863

' COMPRESSOR FOR FLUID PRESSURE SYSTEMS Fi1ed Oct..3l, 1934 IIIIIIIIIIII 1 IQVENTOR Wemaac: [04/1 56 ATTORN EY Patented Sept. 22, 1936 COMPRESSOR FOR FLUID PRESSURE SYSTEMS Wallace F. Oliver, Detroit, Mich... assignor to Hydraulic Brake Company, Detroit, Mich, a corporation of California Application October 31, 193%, gerial No. 750,783

passages on the retraction stroke of the piston.

i Generally these cups have given satisfaction. However, after long usage the cups become deformed, and the material from which the cups are made is forced into the passages. This causes serious damage to the cups and inhibits the free flow of fluid through the passages during the retraction stroke of the piston. The present invention aims to overcome this objection.

An object of the invention is to provide a compression piston having a concentric extension on its head and spaced apertures in the head around the extension of relatively shallow depth and a leak-proof cup supported on the extension so that no portion of the cup may enter the apertures in the head.

Another object of the invention is to provide a cup having a rigid bottom and a flexible wall.

Another object of the invention is to provide a collapsible leak-proof cup provided with a nonfiexible bottom and flexible side walls.

Yet a further object of the invention is to'provide a leak-proof cup having a rigid bottom and flexible side walls provided with grooves or channels arranged to enhance the flexibility of the wall of the cup and to provide for the free passage no oi fluid upon collapse of the cup.

Other objects of the invention will appear from the following description taken in connection with the drawing which forms a part of this specification, and in which,-

Figure 1 is a side elevation, partly in section, of a compressor embodying the invention; Figure 2 is a sectional view of the cup;

Figure 3 is a bottom plan view of the cup; and

Figure 4 is a side elevation of the cup.

5 Referring to the drawing for more specific details of the invention, NJ represents a fluid reservoir having a cylinder M at its base. The cylinder is closed at one end as by a head and is open at its other end, and spaced ports M and I6 arranged in the wall of the cylinder provide communications between the cylinder and the reservoir. The cylinder also has a discharge port it in its head, which may be connected to fluid pressure motors of any preferred type for the actuation of various instrumentalities. 5

A piston 20 reciprocable in. the cylinder is held against displacement by a retaining ring 22 seated in a circumferential groove in the wall of the cylinder adjacent the open end or the cylinder. The piston has a reduced body portion 26 pro- 1o viding in conjunction with the wall of the cylinder an annular chamber 26 communicating with the reservoir it by way of the port M, and a lealrproof cup 28 fitted in a circumferential groove in the skirt of the piston inhibits the passage of 15 fluid from the open end of the cylinder. The head of the piston has a concentric extension Bill of: slight depth, and a plurality of apertures or passages 82 arranged in spaced relation to one another around the extension. These aper go tures provide communications between the annular chamber 226 and that portion of the cylinder forward of the head of the piston.

A check valve 3t seated on the head of the cylinder controls the discharge port it, and a 25 collapsible leak-proof cup it on the extension at of the piston head inhibits the flow or fluid past the piston on its compression stroke and provides for free how of fluid from the annular chamber 26 to that portion of the cylinder forward oi the so piston head on the retraction stroke of the pie ton. A spring it interposed between the check valve 3 5 and the leak-proof cup 36 retains the valve 3d and collapsible leak-proof cup 36 against displacement and also serves to return the piston 3.5 to its retracted position.

I-ieretofore some dimculty has been experienced by reason of deformation of the collapsible leaiiproof cup due to usage, resulting in the material from which the cup is made being forced into the to apertures or passages 32 in the head of the piston. This results in serious injury to the cup and interrupts the how of fluid through the passages on the return or retraction stroke of the piston. To overcome this diihculty, the cup 3% a5 is provided with a metallic bottom tit including a disk having its periphery turned as indicated at 52, and a rubber ring or wall til is moulded on the periphery of the disk. Preferably the wall of the cup tapers gradually outward from the so periphery of the disk to the rim of the cup, and the wall is provided with a plurality of spaced longitudinal grooves 56 communicating with a centrally disposed circumferential groove it. These grooves lend flexibility to the wall of the 55 cup when collapsed.

In practice, during the compression stroke of the piston, the metallic portion of the cup seats on the extension 30 of the piston head and inhibits the rubber portion of the cup from contacting with the head of the piston, thus rendering it impossible to cause damage to the cup or clog the passages 32 in the piston head.

Although I have shown and described a specific embodiment of the invention I am fully aware that many modifications thereof are possible. Therefore the invention is not to be restricted except in so far as is necessitated by the prior art and by the scope of the appended claims.

Having thus described the various features of the invention, what I claim as new and desire to secure by Letters Patent is,

1. A compressor for a fluid pressure system comprising a cylinder, a piston reciprocable in said cylinder, said piston having a forwardly projecting tubular extension and passages through said piston radially outward of said extension, and a packing cup for said piston, said packing cup having a metallic bottom adapted to seat on said extension, said bottom extending across the adjacent ends of said passages in spaced relation thereto, said packing cup including a rubber flange molded to said bottom and extending forwardly of said piston.

2. A compressor for a fluid pressure system of the class described, comprising a cylinder, a pis- .cup and provide for free flow of fluid past the ton reciprocable therein, said piston having a tubular extension projecting forwardly therefrom and passages through said piston located radially outward of said extension, and a packing cup associated with said piston, said packing cup 1 having a metallic bottom adapted to seat on the extension, said bottom extending across the adjacent ends of said passages but spaced from the wall of said cylinder, said packing cup also including a flexible wall attached to said bottom It and bridging the gap between said bottom and said cylinder wall, said flexible wall being adapted to seal against said cylinder wall during forward movement of said piston to prevent flow of fluid therepast but flexing inwardly during reverse ll movement of said piston to prevent flow of fluid therepast.

3. In a compressor for a fluid pressure system, the combination of a cylinder, a piston reciprocable therein, a reservoir communicating with 2( the rear of said piston, said piston having passages therethrough and a packing cup associated with said piston, said packing cup including an imperforate metallic bottom contacting said piston, and a flexible wall attached to said bottom 25 in spaced relation to said passages, said flexible wall sealing against said cylinder during forward movement of said piston and flexing away from said cylinder during reverse movement of said piston.

WALLACE F. OLIVER. 

